KaizenProof

Lesson 17 of 23 · 7 min read

Keep a standard alive: SDCA and PDCA

In Lean: SDCA (standardise, do, check, act)

Builds on: Did it hold?, Write down the best current way

In one minute

A standard starts to fade the day it is written, unless someone keeps it alive. SDCA is the cycle for holding a standard: standardise, do the work that way, check it is followed and still works, and act on what you find. PDCA is the cycle for changing it. Knowing which cycle you are in tells you what to do when you find people working differently from the standard.

The idea

Two cycles work together. Improve it again (in Lean: PDCA) moves the work forward. Hold the standard (in Lean: SDCA, for standardise, do, check, act) keeps the ground already gained. Without SDCA, each improvement slides back. Without PDCA, the standard never gets better.

The SDCA steps:

  • Standardise. The best current way is written down, owned and dated (lesson 16).
  • Do. People work to it, and new colleagues learn it.
  • Check. On a set date, the owner looks at a few real items: is the standard followed, and does it still produce the result? This can be light: a handful of recent cases and one question at a team meeting.
  • Act. If it is followed and working, carry on. If not, find out why before changing anything.
Improve with PDCA, hold with SDCAPDCA moves the work forward. SDCA keeps the new way in place, so the next improvement starts from the higher step.
The PDCA wheel held by the SDCA wedgeA slope rising to the right. On it sits a wheel in four parts, Plan, Do, Check and Act, with an arrow showing it turning uphill: each turn of PDCA lifts the way the work is done. Just downhill of the wheel a wedge marked Standard stops it rolling back: SDCA, standardise, do, check, act, holds the gain. Two smaller wedges further down the slope are earlier standards.PDCAImprove: PDCAeach turn lifts the levelHold: SDCAthe standard stops it sliding backStandard
  • Switch to PDCA when the standard is followed and the problem still happens, or the work has changed.
  • Stay in SDCA when the standard works but is not followed reliably: fix the standard or what gets in its way first.

When people are not following a standard, there are usually three reasons, and "they are careless" is not one of them.

  1. The standard is unclear or hard to find. Fix the standard.
  2. Something gets in the way: a tool changed, a field disappeared, the step does not fit the busiest week. Fix the conditions.
  3. People found a better way. Then the standard is out of date. Test the new way as a PDCA cycle, with a prediction and checks, and if it holds it becomes the new standard.

When to switch to PDCA: the standard is followed and the problem it was meant to prevent still happens; the work has changed (a new tool, a new rule, a new kind of request); or someone has a better idea worth testing.

When to stay in SDCA: the standard works when it is followed, but it is not followed reliably. Inventing something new will not help until you know why the current way is being skipped.

Signs a standard has died: nobody can say where it is; the review date is long past; the owner has left; new people learn the job from a colleague's private notes.

Keep the review cheap, or it will not happen. A few minutes on the review date, by the owner, is enough to keep most standards alive. Retire standards for work that no longer exists; a library full of dead standards hides the living ones.

Example

Illustrative example, not a real company.

An accounts payable team has a standard for setting up new suppliers: the request form requires bank details, a clerk confirms them by phone with the supplier, and a team lead approves.

At the six-month review, the owner looks at a handful of recent set-ups. Most follow the standard, but several sets of bank details were confirmed by email instead of by phone, which is exactly the gap the phone call exists to close.

She asks the clerks what happened. The phone number on the form is usually the supplier's switchboard, so calls go nowhere and clerks fall back on email. Nobody was careless; a condition made the standard hard to follow. SDCA's Act: the form now asks for the phone number of the supplier's accounts contact, and the standard says why.

Later a clerk suggests that suppliers confirm their details through a secure portal the finance system now offers. That is a new way, not a fix to the old one, so it goes through PDCA first, with a prediction and checks, before it replaces anything.

Common mistakes

  • Treating a skipped standard as a discipline problem. Ask what made it hard to follow.
  • Changing the standard on every complaint. A proposed better way is tested as an experiment before it becomes the standard.
  • No owner and no review date. Then nobody notices when the standard dies.

Words to know

  • Hold the standard (in Lean: SDCA): standardise, do, check, act; keeps a working standard in place.
  • Improve it again (in Lean: PDCA): plan, do, check, act; tests a change to the standard.
  • Review date: when the owner next looks at whether the standard is followed and still works.

Check your understanding

3 questions. Answer them all, then check. You can try again as often as you like; nothing about your attempts is kept.

Question 1 of 3The standard says purchase requests go through the request form. At the review, the owner finds several came by email last month. What should she do first?
Question 2 of 3In which cases should the team move from holding the standard (SDCA) to improving it (PDCA)? Select all that apply.

Choose all that apply.

Question 3 of 3At a standard's review, three people explain why step 3 is often skipped. Which reading is flawed?

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Try it on your own work

Describe one recurring task that wastes your time, and see these ideas applied to it.

Report a friction (opens in a new tab)

Worksheet for this lesson: Standard Work Template (free download, no sign-up).

Where this comes from

Pairing a cycle that holds a standard with a cycle that improves it is a common teaching in Lean practice, built on the plan-do-check-act cycle from the quality-management tradition.